Molecular interactions between the olive and the fruit fly Bactrocera oleae

Abstract

BackgroundThe fruit fly Bactrocera oleae is the primary biotic stressor of cultivated olives, causing direct and indirect damages that significantly reduce both the yield and the quality of olive oil. To study the olive-B. oleae interaction, we conducted transcriptomic and proteomic investigations of the molecular response of the drupe. The identifications of genes and proteins involved in the fruit response were performed using a Suppression Subtractive Hybridisation technique and a combined bi-dimensional electrophoresis/nanoLC-ESI-LIT-MS/MS approach, respectively.ResultsWe identified 196 ESTs and 26 protein spots as differentially expressed in olives with larval feeding tunnels. A bioinformatic analysis of the identified non-redundant EST and protein collection indicated that different molecular processes were affected, such as stress response, phytohormone signalling, transcriptional control and primary metabolism, and that a considerable proportion of the ESTs could not be classified. The altered expression of 20 transcripts was also analysed by real-time PCR, and the most striking differences were further confirmed in the fruit of a different olive variety. We also cloned the full-length coding sequences of two genes, Oe-chitinase I and Oe-PR27, and showed that these are wound-inducible genes and activated by B. oleae punctures.ConclusionsThis study represents the first report that reveals the molecular players and signalling pathways involved in the interaction between the olive fruit and its most damaging biotic stressor. Drupe response is complex, involving genes and proteins involved in photosynthesis as well as in the production of ROS, the activation of different stress response pathways and the production of compounds involved in direct defence against phytophagous larvae. Among the latter, trypsin inhibitors should play a major role in drupe resistance reaction.

Analysis of the Olive Fruit Fly Bactrocera oleae Transcriptome and Phylogenetic Classification of the Major Detoxification Gene Families

“…A study which investigated the interaction between B. oleae and olive was recently conducted from the plant perspective [9]. It revealed that the olive response to B. oleae larvae, its most damaging biotic stressor, resulted in the induction of genes implicated in the production of Reactive Oxygen Species (ROS), the activation of different stress response pathways and the production of compounds involved in direct defense against phytophagous larvae.…”

Olive fruits infested with olive fly larvae respond with an ethylene burst and the emission of specific volatiles

“…To further explore the regulation of gene expression induced by ethylene in infested olive fruits, we searched for regulatory motifs involved in ethylene responses in the promoter and 5′‐ and 3′‐untranslated regions (UTRs) of defensive genes ( OeChit , OeTPI2 , and OePRp27 ) ‐ previously reported to be strongly induced in B. oleae ‐infested fruits of cultivar Leccino (Corrado et al ) and in known ethylene‐responsive genes (e.g. OeACO1 , OeACO2 , OeERF1 , OeERF2 , and OeERF3 ).…”

“…Similar defensive genes have been found to be induced in olive fruits under B. oleae herbivory attack. In this regard, chitinases, PR proteins, protease inhibitors, and β‐1,3 glucanases have been found to be significantly induced at the mRNA level in B. oleae ‐infested fruits compared with controls (Corrado et al ). In olive fruits, ethylene also plays a central role in regulating maturation, with the levels of this phytohormone peaking at the later phases of fruit development (Lavee and Martin ; Kitsaki et al ; Tsantili and Pontikis ).…”

Proteome Regulation during Olea europaea Fruit Development

“…To our best knowledge, the 2-D protein profile shown here represents the first proteome map of olive fruit (Figure 2 and Figure 3). So far, only a couple of works focused on olive proteome have been reported in literature [9], [10]. These studies were limited by a common major drawback in plant proteomics: the difficulty in obtaining high quality protein extracts.…”